This invention relates to a hinge mechanism for holding hinge portions in predetermined positions relative to one another, and more particularly to a hinge mechanism capable of urging hinge portions toward predetermined positions when the hinge portions are in intermediate positions between the predetermined positions.
Typical hinge mechanisms consist of a pair of hinge portions, each formed with some structure for receiving an axle, such as a bore, a recess, or an eyelet, and an axle passing through the axle receiving structures of the hinge portions and permitting the hinge portions to rotate relative to one another about the axis formed by the axle. In certain applications, it has been found desirable to use hinge mechanisms having hinge portions capable of being held in particular, predetermined angular relationships relative to one another. It has also been found desirable to use hinge mechanisms having hinge portions that are urged to assume particular, predetermined angular relationships relative to one another when the hinge portions are not already being held in those angular relationships. Such applications include spring loaded, automatically closing refrigerator doors, such as described in U.S. Pat. No. 2,003,274 to Celander, gravity hinges of the type occasionally used in so-called "cafe doors," such as described in U.S. Pat. No. 3,648,327 to Edeus, and multiple position hinges, such as described in the mounting frame of U.S. Pat. No. 4,562,656 to Kristofich.
In hinge mechanisms of the type with which the present invention is concerned, first and second hinge portions are urged toward predetermined angular relationships relative to one another and held in those relationships by male and female engaging members associated with first and second hinge portions. Often, the male engaging member is a rod having V-shaped tips and the female engaging member is a V-shaped groove. As shown, for example, in U.S. Pat. No. 3,460,190 to MacDonald, the male engaging member may be adapted to be axially movable and non-rotatable within one hinge portion, and axially movable and rotatable relative to, and engageable with, the female engaging member on the other hinge portion. In such hinge mechanisms, the female engaging member is non-rotatable and not axially movable relative to the other hinge portion. A spring is provided to urge the male engaging member against the female engaging member such that, when the male and female engaging members are aligned, the hinge portions are held at predetermined angular relationships relative to one another.
Typically, male and female engaging members are arranged on hinge portions such that alignment of the male and female engaging members occurs when the hinge portions are in an angular relationship relative to each other that corresponds to a door closed, a door fully open, or any other desired condition. When V-shaped male and female engaging member are used, there will generally be two hinge portion positions, separated by 180.degree., wherein the engaging members are aligned with one another.
When the male and female engaging members are not aligned, it is possible to cause them to tend toward alignment by providing a spring of sufficient force to overcome frictional forces between the unaligned male and female engaging members. The tendency toward alignment of male and female engaging members can be further enhanced by the selection of particular profiles for the male and female engaging members. It is known, for instance, to use U-shapes, V-shapes, and various other cam profiles for male and female engaging members. Further, the tendency toward alignment will be a function of such factors as the depth of the female engaging member and the height of the corresponding male engaging member, and the use, if any, of lubricant.
Known hinge mechanisms of the type having hinge portions that are capable of being urged toward predetermined angular relationships relative to one another or of being held in predetermined angular relationships relative to one another are generally characterized by their use of numerous parts requiring special machining or forming operations. In the above-cited U.S. Pat. No. to MacDonald, for instance, a door hinge with means for urging hinge portions toward a predetermined position requires a hinge pin to keep the hinge portions aligned over the entire range of motion of the hinge. Further, machining or forming operations to accommodate members for urging hinge portions toward a predetermined position as well as separate machining or forming operations to accommodate the hinge pin passing through each element of the hinge are necessary.